On May 26, 2011, at 1:53 PM, Andy Zhu wrote:
Dat:
1. you can use as.matrix to convert data.frame to matrix;
2. it is likely that the internal representation of your data.frame
may not be numerical value; matrix can only take on numeric.
Not true. Can be any single mode, including "character", "list", and
"logical".
--
david.
--- On Thu, 5/26/11, Dat Mai <dat.d....@gmail.com> wrote:
From: Dat Mai <dat.d....@gmail.com>
Subject: [R] matrix not working
To: r-help@r-project.org
Date: Thursday, May 26, 2011, 12:24 PM
Hello All,
I'm trying to create a matrix from a dataframe (let's call it df):
......a......b.....c.....d
a inputs output
b inputs output
c inputs output
d inputs output
e inputs output
The inputs are represented by columns a and b
The outputs are represented by columns c and d, but the only outputs
are
those from column d
- some values from column d are NA
- column d was created with the code:
df$d=rank(df$c, na.last="keep")
#----------R Code---------#
item=unique(df$a)
n=length(list)
r=matrix(data=NA,nrow=n, ncol=n, dimnames=list(PRR1=item, PRR2=item))
for(j in 2:ln)
{
for(i in 1:(j-1))
{
input1=rownames(r)[i]
input2=colnames(r)[j]
q=df[(df$a==input1 & df$b==input2), "d"]
if(length(q)==0)
{
q=df[(df$a==input2 & df$b==input1), "d"]
}
if(length(q)==0)
{
q=NA
}
r[j,i]=q
r[i,j]=q
r[j,j]=q
}
}
The result is a matrix with the appropriate dimensions, but
everything is
filled with NA instead of the rankings of the various combinations.
I'd like
for the matrix to be filled with the ranking values--what have I
done wrong?
--
Best,
Dat Mai
PhD Rotation Student
Albert Einstein College of Medicine
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______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
